1. Field of the Invention
This invention relates to a combination load-bearing foundation for industrial plants and the like that is also useful as a floatable pallet capable of being supported by a submersible vessel located therebeneath to transport both the pallet and industrial plant or the like and the method of constructing such a pallet of precast, prestressed elements using conventional techniques used in prestressed concrete structures, and thereby avoiding shipyards and costly and complicated special construction techniques.
2. Description of the Prior Art
It has been recognized that it is difficult to construct certain chemical processing plants in some locations because of the difficulty with local conditions. These conditions can be many, but among conditions that cause great difficulty are local unavailability or shortages of materials and equipment from which to make the plant and the unavailability or scarcity of skilled labor with which to carry out the construction. Such conditions do not only exist in underdeveloped countries, but may occur in areas of developed countries, because of specific local unfavorable conditions.
Hence, it has been recognized that there are definite potential advantages in the construction and transport of such plants from a location where building such a plant is favorable to the installation location of the plant where the local conditions are unfavorable.
One such attempt is described in U.S. Pat. No. 3,262,411, Kaltenecker. This patent describes a so-called portable process plant including a base which is a barge, the super-structure of which is independently oceanworthy against all of the strains and stresses encountered by a barge being towed at sea. The barge hull is constructed of reinforced concrete having numerous longitudinal and transverse walls defining compartments. These walls run throughout the breadth and length of the hull and are stated to be essential for rigidity and strength. Other structure is added to further increase its seaworthiness.
Other examples of floating barge constructions, some of which suggest their suitability for carrying all or part of an industrial plant, include U.S. Pat. No. 2,605,733, Smith; U.S. Pat. No. 3,691,974, Seiford, et al.; and U.S. Pat. No. 4,041,721, Kniel. Smith shows a structure of making a unitary barge by clamping together sections of a special design; Seiford, et al., shows another sectionally constructed barge joined together by special junction assemblies; and Kniel shows a compartmentalized hull particularly suited for installation of a natural gas liquification plant.
The following U.S. patents show modular construction for barges, dry docks, boat piers, marinas and the like: U.S. Pat. Nos. 3,665,882, Georgier, et al.; 3,221,696, Gardner; 3,779,192, Gonzalez; 3,983,830, Morgan; 4,067,285, Jones, et al.; and 2,728,319, Engstrand. Georgier, et al., shows a polyhedral modular structure; Gardner shows special universal mechanical couplings for adjacent sections; Gonzalez shows a modular structure, the outside material thereof being specially designed; Morgan shows the method of assembling a modular barge using tensioning cables serially threaded therethrough; Jones, et al., shows a hexagonal structure comprising triangular modules; and Engstrand shows sections particularly suitable for a dry dock, which are assembled in such a way to resist the bending moment of the dock.
The following U.S. patents show multiple barges or floating seaworthy vessels being joined together to function together to support a large load: U.S. Pat. Nos. 3,765,359, Takezawa, et al.; 3,962,981, O'Kon, et al.; and 3,785,314, Scanlan.
One inventor who has been fairly prolific in designing unitary marine structures suitable for support and transport of a large load, such as an industrial process plant, is Alfred A. Yee, who is the inventor named in U.S. Pat. Nos. 3,324,814; 3,833,035 and 4,011,826. U.S. Pat. No. 3,224,814 shows a main framework having a plurality of longitudinally spaced and transversely extending upright open frame-like steel or reinforced concrete rib sections. The other two Yee patents show structures which show the use of honeycomb or vertically extending components, either tangentially joined together or joined together by interconnecting ribs.
In spite of all the efforts expended by Yee and others to construct a suitable floatable plant-carrying vessel, the primary emphasis has been on making such a vessel independently seaworthy (i.e., a self-contained barge), of modular construction either of components to make a barge or of barge components to make a multi-barge vessel, or has been an attempt to develop a superstructure that would be desirably lightweight and capable of bearing a large load. No special attention has been made for providing a structure having fanned out support points and also having numerous long uninterrupted horizontal channels.
Therefore, it is a feature of the present invention to provide an improved floatable pallet for an industrial plant or other large load, comprising precast, prestressed grillage elements arranged in such a way to provide radiating load-bearing, descending through the pallet.
It is another feature of the present invention to provide such an improved floatable pallet having elongated channels therethrough for carrying pipes, conduits and the like needed for connecting together the operating parts of the supported plant.
It is still another feature of the present invention to provide such an improved floatable pallet having grillage elements which are capable of simple fabrication and assembly using techniques well-known in forming prestressed concrete structures, so that the entire pallet can be made without the need for a shipyard or other special construction site.
It is yet another feature of the present invention to provide such an improved floatable pallet fully capable of being borne by a seaworthy vessel or vessels, but itself not having to meet the requirements of having to be independently oceanworthy, and further fully capable of being the support base for the finally installed plant.